The invention is concerned with a process for the preparation of bisphenols and with the bisphenols so prepared.
It is known to prepare bisphenols, e.g., Bisphenol A, by continually rejecting at least 2 moles of a phenol with a carbonyl compound in the presence of an acidic ion-exchange resin in a reaction zone comprising at least two reactors in series and to recover the bisphenol from the effluent from the last reactor, e.g., see U.K. patent No. 883,391. One problem of such a process is that the activity of the resin, especially in the first reactor, decreases with an increasing number of run hours.
It has now surprisingly been found that the activity of the resin does not decrease to any substantial extent if a part of at least one reactor effluent, with the exception of the last reactor effluent, is recycled, preferably to the first reactor.